<?php

/************************************************************************
 * CSS and Javascript Combinator 0.5
 * Copyright 2006 by Niels Leenheer
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


$cache 	  = true;
$cachedir = dirname(__FILE__) . '/js';
$cssdir   = dirname(__FILE__) . '/';
$jsdir    = dirname(__FILE__) . '/js';

// Determine the directory and type we should use
switch ($_GET['type']) {
    case 'css':
        $base = realpath($cssdir);
        break;
    case 'javascript':
        $base = realpath($jsdir);
        break;
    default:
        header ("HTTP/1.0 503 Not Implemented");
        exit;
};

$type = $_GET['type'];
$elements = explode(',', $_GET['files']);

// Determine last modification date of the files
$lastmodified = 0;
while (list(,$element) = each($elements)) {
    $path = realpath($base . '/' . $element);

    if (($type == 'javascript' && substr($path, -3) != '.js') || 
        ($type == 'css' && substr($path, -4) != '.css')) {
        header ("HTTP/1.0 403 Forbidden");
        exit;	
    }

    if (substr($path, 0, strlen($base)) != $base || !file_exists($path)) {
        header ("HTTP/1.0 404 Not Found");
        exit;
    }
    
    $lastmodified = max($lastmodified, filemtime($path));
}

// Send Etag hash
$hash = $lastmodified . '-' . md5($_GET['files']);
header ("Etag: \"" . $hash . "\"");

if (isset($_SERVER['HTTP_IF_NONE_MATCH']) && 
    stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) == '"' . $hash . '"') 
{
    // Return visit and no modifications, so do not send anything
    header ("HTTP/1.0 304 Not Modified");
    header ('Content-Length: 0');
} 
else 
{
    // First time visit or files were modified
    if ($cache) 
    {
        // Determine supported compression method
        $gzip = strstr($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip');
        $deflate = strstr($_SERVER['HTTP_ACCEPT_ENCODING'], 'deflate');

        // Determine used compression method
        $encoding = $gzip ? 'gzip' : ($deflate ? 'deflate' : 'none');

        // Check for buggy versions of Internet Explorer
        if (!strstr($_SERVER['HTTP_USER_AGENT'], 'Opera') && 
            preg_match('/^Mozilla\/4\.0 \(compatible; MSIE ([0-9]\.[0-9])/i', $_SERVER['HTTP_USER_AGENT'], $matches)) {
            $version = floatval($matches[1]);
            
            if ($version < 6)
                $encoding = 'none';
                
            if ($version == 6 && !strstr($_SERVER['HTTP_USER_AGENT'], 'EV1')) 
                $encoding = 'none';
        }
        
        // Try the cache first to see if the combined files were already generated
        $cachefile = 'cache-' . $hash . '.' . $type . ($encoding != 'none' ? '.' . $encoding : '');
        
        if (file_exists($cachedir . '/' . $cachefile)) {
            if ($fp = fopen($cachedir . '/' . $cachefile, 'rb')) {

                if ($encoding != 'none') {
                    header ("Content-Encoding: " . $encoding);
                }
            
                header ("Content-Type: text/" . $type);
                header ("Content-Length: " . filesize($cachedir . '/' . $cachefile));
    
                fpassthru($fp);
                fclose($fp);
                exit;
            }
        }
    }

    // Get contents of the files
    $contents = '';
    reset($elements);
    while (list(,$element) = each($elements)) {
        $path = realpath($base . '/' . $element);
        $contents .= "\n\n" . file_get_contents($path);
    }

    // Send Content-Type
    header ("Content-Type: text/" . $type);
    
    if (isset($encoding) && $encoding != 'none') 
    {
        // Send compressed contents
        $contents = gzencode($contents, 9, $gzip ? FORCE_GZIP : FORCE_DEFLATE);
        header ("Content-Encoding: " . $encoding);
        header ('Content-Length: ' . strlen($contents));
        echo $contents;
    } 
    else 
    {
        // Send regular contents
        header ('Content-Length: ' . strlen($contents));
        echo $contents;
    }

    // Store cache
    if ($cache) {
        if ($fp = fopen($cachedir . '/' . $cachefile, 'wb')) {
            fwrite($fp, $contents);
            fclose($fp);
        }
    }
}	
